Description
The Topcon 360° Sliding Prism ATP1S (ATP1SII) is a 360° prism made by Topcon and also sold under the Sokkia brand.
Its absolute prism constant is -7.0 mm, which is +27.4 mm on the Leica scale.
Specifications
| Model: | ATP1S / ATP1SII |
| Manufacturer: | Topcon |
| MPN: | Unknown |
| Status: | Current |
| Absolute constant: | -7.00 mm |
| Leica constant: | +27.40 mm |
| Constant source: | Manufacturer documentation |
| Maximum range: | 1,000 m (1.3 to 1,000 m (GT datasheets, ATP1/ATP1S row)) |
| ATR / tracking range: | 600 m |
| Mount: | Sliding prism on pole |
| Equivalents: | ATP1 optics in a sliding mount |
| Last verified: | 21/10/2026 |
Sources
Topcon 360° Sliding Prism ATP1S (ATP1SII) FAQ
Below is a list of frequently asked questions about Topcon 360° Sliding Prism ATP1S (ATP1SII).
What is the prism constant for the Topcon 360° Sliding Prism ATP1S (ATP1SII)?
The absolute prism constant for the Topcon 360° Sliding Prism ATP1S (ATP1SII) is -7.0mm. The Leica constant is 27.4mm.
Can I use the Topcon 360° Sliding Prism ATP1S (ATP1SII) with a Leica instrument?
Yes, just set the prism constant to 27.4mm.
